AES256对称加密

需要引入bouncycastle库的jar包

package test;

import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.SecureRandom;
import java.security.Security;
import java.util.Base64;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.SecretKeySpec;

public class Aes256Util {
    private final static String PROVIDER_BC = "BC";
    private final static String CHARSET = "UTF-8";
    private final static String ALGORITHM = "AES/ECB/PKCS5Padding";
    private final static String KEY_ALGORITHM = "AES";

    /**
     * 引入BC库
     */
    static {
        try {
            Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 初始化一个256位对称加密的秘钥
     * @param keyStr 如果加密解密的方法直接用一个String.getByte()的话，那么这个key需要达到128/192/256 bits
     * @return
     */
    public static byte[] getRandomKey(String keyStr){
        KeyGenerator keyGenerator = null;
        SecureRandom secureRandom = null;
        try {
            keyGenerator = KeyGenerator.getInstance(KEY_ALGORITHM);
            secureRandom = SecureRandom.getInstance("SHA1PRNG");
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        secureRandom.setSeed(keyStr.getBytes());
        keyGenerator.init(256, secureRandom);
        return keyGenerator.generateKey().getEncoded();
    }

    /**
     * 加密
     * @param content 原明文串
     * @param key 对称加密秘钥
     * @return 最后对byte进行了base64encode
     */
    public static String encrypt(String content, byte[] key){
        String encryptStr = "";

        try {
            //密码器初始化
            Cipher cipher = Cipher.getInstance(ALGORITHM, PROVIDER_BC);
            SecretKeySpec secretKeySpec = new SecretKeySpec(key, KEY_ALGORITHM);
            cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
            byte[] encryptByte = cipher.doFinal(content.getBytes(CHARSET));

            encryptStr = Base64.getEncoder().encodeToString(encryptByte);

        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (NoSuchProviderException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        } catch (BadPaddingException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }

        return encryptStr;
    }

    /**
     * 解密
     * @param contentByte 加密后的密文byte
     * @param key
     * @return
     */
    public static String decrypt(byte[] contentByte, byte[] key){
        String decryptStr = "";
        //密码器初始化
        try {
            Cipher cipher = Cipher.getInstance(ALGORITHM, PROVIDER_BC);
            SecretKeySpec secretKeySpec = new SecretKeySpec(key, KEY_ALGORITHM);
            cipher.init(Cipher.DECRYPT_MODE, secretKeySpec);
            byte[] encryptByte = cipher.doFinal(contentByte);

            decryptStr = new String(encryptByte, CHARSET);

        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (NoSuchProviderException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        } catch (BadPaddingException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }

        return decryptStr;
    }

    public static void main(String[] args) {
        String keyStr = "1111111111111111111111111111111";

        byte[] rkey = getRandomKey(keyStr);

        String a = encrypt("test", rkey);

        String b = decrypt(Base64.getDecoder().decode(a), rkey);

        System.out.println(a);
        System.out.println(b);
    }
}